Biodiversity

It refers to two aspects of organisms in a given environment. 1) The number of species, 'species richness'. 2) The number of organisms within each species.

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What does biodiversity mean?

Living differences

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Is biodiversity constant?

No.

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What do the number of species and organisms depend on?

The environment.

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What happens at high light intensity?

More plants grow at high light intensity than low light intensity, a bright environment can support more herbivores and therefore more carnivores than a dull way.

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What happens with more energy flowing through an ecosystem?

It produces more species and more individuals. Equatorial regions have a much higher biodiversity than polar regions.

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Where are biodiversity hotspots?

They cluster around the equator and tropics, where high light intensity all year ensures high energy inputs into the ecosystems.

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What is succession?

The change in the composition of a community over a period of time. It increases animal biodiversity but decreases plant biodiversity.

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What is natural selection?

This can generate and change biodiversity

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What is human influence?

Human activity making the environment less hospitable to living organisms.

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How has human influence had an impact on the tropical rainforests in Brazil and Costa Rica?

Farming roads and industry destroyed habitats, reduced the number of individuals and driven many species to extinction

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How has human influence had an impact on oceans?

Over-fishing and depleted fish stocks and some very productive diverse areas such as coral reefs are severely stressed. Trawlers dredging the ocean floor disrupt habitats, damaging populations of invertebrates, fish and sea mammals.

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How has human influence had an impact on land?

Misuise of land such as trampling by cattle, as well as increased temperature has increased the area of deserts. The Sahara Desert has expanded and large areas of Australia and North America are vulnerable.

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How has human influence had an impact on rivers?

They've been polluted with industrial chemicals. The Yangtze River dolphin, baiji, was declared extinct in 2007. Problems were made worse by capture and collisions with river sraffic.

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How has human activity enhanced biodiversity?

The River Thames, they built sewers, restoring biodiversity and it was recovered by the 1970's. (refer to notes for more)

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What plants and animals are used to support human civilisation?

A small number of plant species provide staple foods, wheat and rice. Medicinal drugs are derived from plants and fungi. Living organisms provide raw material.